In some instances it is desirable for security reasons to require that the user of a data-processing system (e.g., a wireless telecommunications terminal such as a cellular phone or a smart phone, a personal computer, a server, etc.) be authenticated before the user is permitted to access an application or resource of the data-processing system. Typically a user is presented with an authentication challenge, and the user must supply a valid response to the challenge. Examples of different types of authentication challenges include:                requiring a user to furnish his or her username and password;        requiring a user to consult an electronic token device or a list of numbers in order to furnish a one-time password;        requiring a user to answer a pre-arranged secret question (e.g., “What is your mother's maiden name?”, “What was your first telephone number?”, etc.); and        biometrics (e.g., fingerprint recognition, voice recognition, retinal or iris scan, etc.).Furthermore, in some instances the user of wireless telecommunications terminal might be periodically challenged (i.e., the user is periodically re-authenticated) for greater security.        